1. Technical Field
The present disclosure relates to a method for fabricating a light emitting diode (LED).
2. Description of the Related Art
LEDs are semiconductors that convert electrical energy into light. Compared to conventional light sources, the LEDs have higher energy conversion efficiency, higher radiance (i.e., they emit a larger quantity of light per unit area), longer lifetime, higher response speed, and better reliability. At the same time, LEDs generate less heat. Therefore, LED modules are widely used as light sources in optical imaging systems, such as displays, projectors, and so on.
A conventional method of fabricating the LEDs includes the following steps. A GaN bumper layer, a GaN layer, an N-type GaN layer, an active layer and a P-type GaN layer are deposited on a substrate. The active layer is made of InGaN or GaN. The P-type GaN layer and the active layer are etched via inductance-coupling plasma etch process, thereby exposing a surface of the N-type GaN layer. A nickel layer and a gold layer are deposited on a top surface of the P-type GaN layer via electron beam evaporation process. Then, the nickel layer and the gold layer are annealed for 10 minutes, whereby a transparent contact layer forms on the P-type GaN layer. An indium tin oxides (ITO) layer, which functions as transparent conductive film, is sputtered on a portion of the transparent contact layer. A titanium layer and an aluminum layer, which function as electrodes, are formed on the N-type GaN layer and the remaining portion of the transparent contact layer. Finally, the ITO layer is etched via inductance-coupling plasma etch process to roughen a top surface of the ITO layer, thereby improving the light extraction efficiency of the LEDs. In the above method, the ITO layer is formed on the transparent contact layer via sputtering, and then is to etched to roughen the top surface thereof, which results in a complex manufacturing process and a high manufacturing cost.
What is needed, therefore, is a method for fabricating a light emitting diode, which can overcome the above-described shortcomings.